Harassment & Non-Stop Calling

Agents have been calling me up to 6 times a day, with the rudest attitudes and bullying type language. They are incessant and behave and speak as if I owe them money personally. I have spoken to a supervisor (who was as rude as the worst of them) and tried to talk to him, but he was as uncaring and useless as a match in the rain. I am so close to laying a charge of harassment against them.